My colleague bought a banana at a Tesco Metro this week. For 7p. It will probably cost more than 7p to dispose of the skin. Plantations in the West Indies may go bust, but hey, who cares?

The giant supermarkets are the masters of driving suppliers to the wall, or close to it. They excel at keeping pay levels for their workers only just above minimum wage. They use every retailing trick to encourage us to buy stuff we don't really need, and cover it all in pointless packaging.

And it is this business model that is held up as the future for financial services.

Tesco has ruled out buying Northern Rock, but promises as many as 1,000 jobs in the north east as it expands its Tesco Bank.

Treasury officials, desperate to raise cash, will in all likelihood flog the "good" bit of Northern Rock to the first serious bidder. Maybe that will be Sir Richard Branson. Maybe it will be another supermarket chain, or possibly a foreign bank.

Let's not forget that it was Asda's Andy Hornby who took over Halifax Bank of Scotland and was in charge when it fell into public hands. His appointment prompted much breathy comment about the lessons for banks from the supermarkets. In truth, there weren't any.

Since its rescue by taxpayers, we have stumped up £27bn to keep Northern Rock afloat. What will we get back from a trade sale to a private buyer? At its February 2007 peak, Northern Rock's market capitalisation was around £5.3bn. So a private (fire) sale will not come anywhere close to recompensing the taxpayer. A better solution, but one resisted by "get it off the books at any price" government officials, is to remutualise the bank.

Northern Rock, Alliance & Leicester, Bradford & Bingley and the daddy of them all, Halifax, prospered for years as mutuals. Only after they floated, lined the pockets of the investment banks, borrowed recklessly on wholesale markets and paid themselves bloated bonuses did they fall apart and come to us with a begging bowl.

In France and Germany, where GDP is recovering, a much healthier financial sector has mutuality at its core. In Britain, we should be encouraging a new financial landscape that is less prone to speculative activity – smaller but more sustainable – making low-ish returns in a low-risk environment. That alone should scare off stockmarket investors and ensure we never have to bail the banks out again.

The stumbling block is the need for quick-fix solutions to the public finances. It's entirely understandable that taxpayers are baying for their bailout money back.

Firstly, we need to understand the make-up of that £27bn bailout. Much of it was to allow loans to be rolled over, and will eventually be repaid, whatever form the bank takes in future.

The Oxford report recommends the government explores a new building-society instrument – called profit participating deferred shares – that could be issued to UKFI (the body in charge of Northern Rock) as consideration for its equity. It should do so urgently.

The lesson of the past two years is that an unrestrained private financial services sector has catastrophic consequences for us all. Surely we don't want Northern Rock thrown back into that maelstrom?